Froth flotation process



Patented July 7, 1931 CRIN :o. CUNNINGHAM, or INDIANAPOLIS, INDIANA, AssIoNoR "ro PETER OF INDIANAPOLIS, INDIANA FROTH FLOTATION PROCESS No Drawing. Application filed September 10, 192B, Seri al No'. 305,143. Renewed February 19, 1931.

This invention relates to the froth flotation process for the recovery of ores and minerals .and has for its object the use of a certain class of organic substances in the concentration ofsuch ores and minerals.

The present invention is based on the discovery that the xanthogenates' of certain al- I cohol-like cyclic and heterocyclic compounds are very effective flotationfcollecting reagents.

compounds p ossess the property of reacting with alkali metal hydroxides and carbon .disulfide to form xanthogenates, said or-. ganic compounds can be characterized by benot enter into reaction with an alkali metal hydroxide and carbon disulfide, as do their 3 corresponding hydrogenated derivatives,

cyclohexanol and the methyl cyclohexanols respectively; this difierence in chemical behavior being due to the fact that the hydrogenation of unsaturated (benzenoid structured) aromatic compounds transforms them to saturated (or more completely saturated) compounds possessing aliphatic-like properties, hydrogenation thereby imparting to hydroxy-aromatic compounds (phenol, cre sols, and the like) the property, characteristic of the aliphatic alcohols (alkyl hydroxycompounds), of reacting with alkali metal hydroxide and carbon disulfide to form xanthogenates, although not to such a pronounced degree. Accordingly, the hydrogenated hydroxy-aro'matic compounds are commonly called cyclic or heterocyclic alcohols, a class of substances distinguished from the true aliphatic alcohols by their ring 50 structure.

Certain ring-structured organic c. ItnILnY.

Since: alcohol-like I properties are. tosome i extent imparted to hydroxyz-aromatic com pounds when theyare only partially saturated with hydrogen, as for example the di and tetrahydro derivatives of phenol the c'resols and the like, it is not desired to limit the classification of the compounds of this invention that. form active xanthogenate flota tion reagents to the completely hydrogenated compounds, but to include also the hydrogenated hydroxy-aromatic derivatives of any degree of hydrogenation, such as di, tetra, and hexahydro compounds, etc.

"The cyclic alcohols-being verygood froth s ing agents (as set forth ina companion ap-' plication, Serial No. 305,142 filed concurrentg 1 1y herewith), the preparation of. the xanthogenate collecting reagent of this invention.

may very conveniently be made'up in such I proportions as to have present in thepreparationan excess of the cyclic alcohol to serve as a frothing agent, the resulting. product I thus serving ing reagent. I

As specific examples, the following meth-. ods are given for preparing the cyclic and heterocyclic alcohol xanthogenate flotation both as a collecting and frothreagents of this discovery, without restricting the invention to these examples.

I Ewample 1 8.3 parts, of the hydrogenated cresols (O, M, P mixed) and 2.9,parts of sodium hydroxide were thoroughly ground together in a mortar at the temperature of a steam bath for about 15- minutes and after cooling,

5.5 parts of carbon disulfide (CS were added and the grinding continued (more CS being added as it evaporated)-until the reaction was complete, as shown by the con-.

stancy of the weight. These proportions are the theoretical for completely converting the hydrogenated cresols to the xanthogenate compound and under the conditions of this preparation about of the carbon disul- 'fide entered into reaction. The product of Example 2 8.3 parts of hydrogenated cresols were reacted with 0.57 parts of sodium hydroxide (NaOI-I) b grinding together at the temperature o paste was obtained, cooling, and then reacting with 1.1 parts of carbon disulfide as above ditionsor proportions or materials, of the above preparations, but may use a lower temperature such as room temperature for carrying out the first step in the preparation, or

instead of carrying out the reaction in two steps, the reacting substances (hydrogenated cresols, alkali and CS may be ground together in a one step operation, other alkaliescan be used as well as other hydrogenated hydroxy-aromatic bodies, or mixtures thereof.

I Example 3 For the preparation of a combined frothing and collecting agent from steam distilledpine oil (terpineol or terpenealcohol), 7.36 parts of pine oil and 0.9 parts of sodium.

E mample 4 8.3 parts of pine oil, 2.1 parts of sodium hydroxide and 4.0 parts of carbon disulfide were reacted together as above to give a combined frothing and collecting reagent (0.30 lb. of reagent per ton of ore giving very satisfactory recoveries on the ore tested).

In the case of solid cyclic (or heterocyclic) alcohols, like menthol and borneol, the xanthogenate reaction may be carried out as above by first dissolving the alcohol substance in some inert solvent like toluene, treating with alkali metal hydroxide and carbon disulfide (in one or two steps) then vacuum-distilling off the solvent.

In the above examples sodium hydroxide is used in preference to-potassium hydroxide because of the greater stability of the flotation reagent formed, but the invention is not restricted to the use of sodium hydroxide alone, nor to the use of the alkali metal hydroxide in the solid form, since in some a steam bath. until a smoothcases a concentrated alkali metal h droxide solution in water may be used, or or other preparations metallic sodium may be employed.

The reactions taking place may be explained as follows (using hydrogenated phenol), to the correctness of which theory the invention is not restricted.

0H +NaOH= ONa H H H H 8 H 41 ON: 4.03,: 0- SNa H H The products obtained, as those illustrated in the above examples, were employed in the flotation of a copper sulfide ore, of the Utah Copper Co., analyzing about 1.0% co per, in the ratio of about one tenth pound 0.1 lb.) of product per ton of dry ore, and for the products requiring a frothing agent pine oil was used. The ore was subjected to the ordinary flotation operation in a mechanical agitation type of flotation cell, and a lime circuit employe A tailing analyzing 0.10% copper or under was obtained, together with a high grade concentrate, corresponding to a recovery of about 90% of the copper value in the ore treated.

In other tests both smaller and larger amounts of the reagents of this invention have been employed, in the flotation of ores, with satisfactory results, and the said new reagents have been used both alone and with other flotation, reagents, with satisfactory results. Furthermore, the conditions for carrying out a flotation operation may be varied widely from those included in the above examples and any type of flotation machine can be used, or, instead of an alkaline circuit, a neutral or acid circuit can be used.

In the above specification reference has been made to the use of hydrogenated phenol and cresols in the preparation of a satisfactory flotation reagent. It is to be understood that other closely analogous substances, such as hydrogenated tar acid (from either high or low temperature tar) can likewise be employed within the scope of the invention.

Claims 1. A process which comprises froth flotation of ores in the presence ofa xanthogenate of a hydrogenated hydroxy-aromatic derivative together with a hydrogenated hydroxyaromatic derivative as a frothing agent.

4. As a new composition of matter, a mixture comprising a hydrogenated hydroxyaromatic derivative and a xanthogenate of a h drogenated hydroxy-aromatic derivative, v suc composition having collecting and frothing properties. I

In testimony whereof I have signed my name to this specification.

ORIN D. CUNNINGHAM. 

